Quite a lot of people today prefer wearing contact lenses to glasses. Some people use contact lenses for aesthetic reasons, as they believe that glasses make them look awkward. Other people value the freedom of movement that contact lenses give, which is advantageous when e.g. playing a game of soccer or attending a high-impact aerobics class. Then again some people just do not like the inconvenience of polishing greasy glasses.
Even though contact lenses have been improved during the last decades and posses many advantages in comparison to glasses, contact lenses still need to be disinfected and cleaned periodically, in most cases every day, to avoid infections and discomfort for the wearer.
The development of products for disinfection and cleaning of contact lenses have made the "daily task" easier. However, most contact lens users still regard the disinfection and cleaning task as a troublesome task.
Whether the contact lenses are hard or soft, opticians usually recommend to disinfect the lenses daily and clean them weekly.
Disinfection prevent growth of bacteria on the surface of the contact lenses which might lead to infection of the eyes and making it impossible to wear contact lenses for days.
Cleaning is normally performed by an enzyme capable of degrading debris and/or soil build up on the contact lenses surface. These deposits reduce the wearing comfort as only a reduced amount of oxygen is capable of penetrating the contact lenses to the eyes, and as the friction between the eyes and the contact lenses is increased.
After a cleaning and/or disinfection procedure the contact lenses need to be rinsed thoroughly to remove all enzymatic activity and/or disinfecting agent, e.g. by using a physiological saline solution.
In the case of the disinfecting agent being hydrogen peroxide a number of catalases have been known to be used as neutralizing agents.
Catalases E.C. 1.11.1.6 (Enzyme Nomenclature, Academic Press, Inc, 1992) are enzymes which catalyze the conversion of hydrogen peroxide (H.sub.2 O.sub.2) to water (H.sub.2 O) and oxygen (O.sub.2).
A plethora of methods for disinfection and cleaning of contact lenses are known. Proteases are often used for cleaning contact lenses as described in U.S. Pat. No. 3,910,296 (Allergan).
CA 1,146,881 (Bedding) concerns a method for cleaning contact lenses using enzymes, where the cleaning procedure is followed by rinsing of the lenses, e.g. with saline, to remove active enzymes from the lens.
U.S. Pat. No. 4,670,178 (Allergan) discloses a method for simultaneous cleaning and disinfection of contact lenses with a protease in hydrogen peroxide. The cleaning is effected by presence of protease activity and shown to be very efficient. After the cleaning and disinfection procedure the activity of the disinfecting and cleaning agent need to be removed from the lenses before use.
EP patent application No. 147,100 (Ciba Geigy) concerns cleaning and disinfection of contact lenses with a hydrogen peroxide solution in the presence of a solid sustained release composition which slowly releases a peroxide inactivator. The lenses may be treated with a wetting or comfort solution before inserting into the eyes. However, cleaning and disinfection with hydrogen peroxide does not remove proteinaceous deposits effectively from the surface of the contact lenses.
WO 86/07264 (Kellway Pharm. Ltd.) describes a method for disinfection and cleaning of contact lenses with hydrogen peroxide using a catalase immobilized in a container for neutralization of the hydrogen peroxide. This way excess hydrogen peroxide is decomposed without washing and rinsing.
WO 93/17721 (Genencor Int. Inc.) describes an improved method for cleaning and disinfection of contact lenses comprising disinfection with hydrogen peroxide and decomposition of the residual hydrogen peroxide in the solution with catalase enzyme (CatR) derived from the filamentous fungus Aspergillus niger.
WO 95/02044 (Novo Nordisk A/S) concerns two acidic proteases active in the presence of hydrogen peroxide in concentrations up to as high as 5 wt. %. Example 5 of said application describes cleaning and disinfection of contact lenses using one of said acidic proteases as the cleaning agent and hydrogen peroxide as the disinfecting agent. Further, it is mentioned that catalase may be used for neutralization of the hydrogen peroxide.
Cleaning and disinfection of contact lenses is regarded as a troublesome daily task by most contact lens wearer. Further, prior art methods for disinfection and cleaning of contact lenses are not very safe and consumer convenient as the risk of e.g. forgetting a step is very much present, as at least two not continuous steps need to be carried out.
Therefore, there is a need for more safe and consumer convenient disinfection and cleaning methods and systems. A one-step disinfecting and cleaning systems for contact lenses would increase the safety and consumer convenience.